Stirred ball mills (also known as attritors) are commonly used for material processing. They are very flexible machines that can perform mechanical alloying, grinding, particle size control and mixing. They can be configured vertically or horizontally to optimize a particular process. A stirred ball mill works by loading grinding media, which can be spherical, cylindrical, etc., into a vessel along with the material to be processed. This load is then stirred to the appropriate speeds by spinning arms driven by an externally-mounted motor. A typical stirred ball mill is limited to one reaction at a time. This means performing process optimization or running different materials has to be done sequentially, taking a great deal of time.
If the process needs to be carried out under a controlled atmosphere (e.g., with inert or a specific gas to assist the reaction or process), a seal must be made around the shaft from the driving motor to the stirring arms. If this rotating seal fails, the reaction is ruined. Also, for a small reaction, the vessel is loaded in a glove box, and if the seal is not perfect, it will leak before the user can load the cup on the stirred ball mill and connect an external gas source. Often this is prevented by placing the entire stirred ball mill in a controlled atmosphere, an expensive and cumbersome solution.